Range finder



O. LIEBMANN RANGE FINDER Filed July 20, 1939 Jan. 9, 1940.

I /6 -mm .eoT i..- a

zhlvrihrrolz.l Oscarl. Lebma 11n BY la.. @vf/Ww ATTORNEY.

Patented Jan. 9,

' lUlxurlazl) STATES PATENT OFFICE RANGE FINDER .Oscar Liebmann, Bergeniield, N.IJ., assigner to Q.10. S. Corporation, New York, N. Y., a corporation of York Application July zo, 1939, serial No. 285,528

1 01am. (c1. sii-2.4)

My invention relates to improvements in range finders -of the type which are used -either separately or fastened to a camera, to read the correct distance, whereupon the camera lens is focused, and which consist primarily -of a flxed semi-transparent reflector and a rotatable reilector mounted at a certain distance away from thejiixed one and with finely adjustable means for turning the rotatable reector and calibrated indicating means from which the distance may Other' objects and advantages of my invention will be apparent during the courseof the following description.

In the accompanying drawing, forming part of this specigcation, and in which like numerals are employed to designate like parts throughout the same, l

Figure 1 is a side view of a range ,nder embodying my invention,

Figure 2 is arear elevation of the range nder.'

80 Figure is a section along line 3-1-3 in Fig. 2,

and,

Figure 4 is a front elevation of the range finder. In the drawing, wherein for the purpose of i1- lustration, is shown a preferred embodiment of as my invention, the numeral I0 designates a housing of tubular shape and square cross section. On one of its four sides the tubular housing I0 has two projections II and I2 each of which con- 4tain a glass window I3 which is held in place by a washer I4 which has a substantially square aperture. Suitable lenses could replace the glass windows, if desired. A spring washer I5 is placed behind the glass in order to prevent cracking of same.

On the opposite side of the tubular housing. in

respect to the projection I2, is another projection I6 inside of which is another glass window or lens I1 backed by a spring washer I8 and held in place by the eye piece I9. The ends of the-tubular housingare closed up by covers 20. Inside the tubular housing, between projections I2 and I6 is mounted a xed reflector" 2| which is held rigidly in a 45l degree angleby mounting 22 and which again is secured to the side wall of the u tubular housing by rivets 23.

Inthe other end of the-tubular housing is mounted a. rotatable reector 24 which is directly inside the window II. The reflector 24 is not transparent and is adjustable in such a position that light coming in through window Il will be reflected parallel to the axis of the tubular housing and will hit the rear face of the semitrans' parent reector 2I which `will reflect the light out through window I1 'to the eye of the observer.y

4This is possible because mounting 22 has an'openl. ing' 25 through which the light may pass. At the same time light may pass directly in through window I2, through the semitransparent reflector 2| and out again through window I1 tothe eye -l of the observer.

Reflector 24v 1s nxed to' lever ze' which is pivoted upon shaft 21 which again is journalled in both sides of the tubular housing I0. The lever 26 is movable one way by spring 28 which is fastened to one end of the lever with screw 29. To move 20 thel lever 23 in the opposite direction one turns the knurled knob 30 which has a threaded sleeve l3l which runs in threads in the tapped bushing.

The bushing 32 is fastened to`the tubular housing I0 by screws 33 and 3l. The screw 34 also serves 25 as a stop against which the end of screw 35 will strike at the end of .its travel. The screw 35 is fixed in knob 30. A dial plate 33 is fastened to knob 30 b y screw 31 and carries divisions which indicate the distance directly in units of length. 30 A set screw 38 may be reached by removing screw 31 and by which the position of the rotatable reflector 24 may be set to the correct reading of distance as indicated on the dial 36. To prevent tampering with the adjustment of .screw 33 the 35 lock screw 31 does not have the usual slot for a screw driver, but must be removed'by a special t key ttlng into hole 39.

On one lside of the tubular housing I0 is pro- -vided a solid projectionwlrilch. serves as a base o for mounting. In Fig. 2 is shown the usual method of mounting comprising a channel strip '4I which is fastened to base 40 by screws 42.` The bent up. edges of channel 4I t into a recep tacle 42 which may be fastened to a camera by 45 screws 44. 'Ihe channel 4I is'slidable in receptacle I3 and thus the range finder may be removed without unloosening any screws. Y

Thel operation o f my invention is based upon the well known principle illustrated in Figure 4 50 of my copending application, Serial No. 257,038, filed Feb. 18,1939. The range' finder isheld ina convenient position with the eye piece I9 in front of one eye and the knob 30 isturned either one tures is obtained. The pointer mounted upon the projection 4B will then point to a given numeral on the dial which will indicate the distance of the object. The lens of the camera is then set for this distance manually.

It is to be understood that the form of my in? vention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention, or the scope of the subjoined claim.

Having thus described my invention, I claim:

- In a range finder of the character described a` tubular housing closed at-both ends; two substantially square windows in said housing, one near each end of the housing and located on one of the four sides of same; a viewing aperture on the opposite side of the housing and in line with one of the square windows; a fixed semi-trans- I the other end of the lever, said lever and spring being located at one end of the tubular housing; a tapped bushing fastened to the rear side of the tubular housing; a finely threaded hollow sleeve one end of which has a large head, said threaded sleeve running in the tapped bushing; a dial plate fastened on the flat top of the head; an adjustable set-screw in said hollow sleeve in engagement with the reflector lever; a lock screw closing the outside opening of the hollow sleeve, and stops limiting the rotation of the dial.

OSCAR LIEBMANN. 

